Automobile exhaust purifying system

Abstract

An exhaust purifying system for an automobile engine including an exhaust system for the emission of exhaust gases to the atmosphere through a catalytic converter. The system comprises a temperature detector for detecting a signal indicative of the temperature of the catalyst, a total engine operating hour detector for detecting a signal indicative of the total operating hour over which the engine has been operated, a spark timing control for retarding the spark timing when the temperature detector detects that the catalyst temperature is lower than a predetermined value, and a retard time corrector for increasing the amount of control to be performed by the spark timing control with increase within a predetermined range detected by the total engine operating hour detector.

We claim: 
     
       1. An exhaust purifying system for an automobile internal combustion engine which comprises, in combination: a catalytic converter disposed on an exhaust system of the engine and having a catalyst;   a temperature detecting means for detecting a signal indicative of the temperature of the catalyst;   a total engine operating hour detecting means for detecting a signal indicative of the total operating hour over which the engine has been operated;   a spark timing control means for controlling the spark timing to retard when said temperature detecting means detects that the temperature of the catalyst is lower than a predetermined value;   a retard time correcting means for increasing the amount of control performed by the spark timing control means with increase within a predetermined range detected by said total engine operating hour detecting means.   
     
     
       2. A system as claimed in claim 1, wherein said total engine operating hour detecting means comprises an integrating odometer for detecting the total running distance of the automobile driven by the internal combustion engine. 
     
     
       3. A system as claimed in claim 1, wherein said temperature detecting means comprises a catalyst temperature sensor. 
     
     
       4. A system as claimed in claim 1, wherein said temperature detecting means includes a start detecting means for detecting the passage of a predetermined time subsequent to the start of the engine. 
     
     
       5. A system as claimed in claim 1, wherein said total engine operating hour detecting means comprises an integrating counter for counting the total engine operating hours.